You all are not seeing the forest for the trees. Using a sci-fi film as the yardstick for what interoperability should look like is silly.
(This is in response to the general angst over interoperability, not the IOT space, which I agree is underwhelming at the moment. However, in what I assume to be opposition to most people in this thread, I am hugely optimistic (if not yet invested).)
Sure, every once in a while something that would appear to be easy turns out not to be, and that's really annoying. But most things works well most of the time. Transferring state between devices? That's the cloud. My email is in sync 100% of the time between 4-5 different computers and devices of different brands and OSs. Dropbox takes care of my personal files, box.com of those for work. I frequently collaborate on documents in both Google Docs and Quip. Not too long ago, transferring files between Mac and Windows was hard (I think macs had a proprietary compression program that wasn't available on windows?) - luckily that's entirely in the past. USB is ubiquitous, FireWire, PS/2, ADB, serial, all gone. A Mac keyboard works on a Windows box, and vice-versa. Bluetooth definitely has kinks, but it also has a lot of "just works" along very long stretches. With a few annoying exceptions, people using Linux, Macs and Windows can work together seamlessly. Websites (with a few annoying exceptions) generally works well in all major browsers on all major platforms, on desktop, tablets or mobile (both IOS, Android and Microsoft). I got a new wifi-printer a few days ago - after joining to the network, it was automatically available on our computers. Took maybe five minutes, no messing about with IP addresses and drivers.
I can cast to a ChromeCast on my TV from my Mac, my Android and random guests iPhones (I can also "cast" Youtube directly to the TVs Youtube app, but it's pretty flaky -- and this is some fancy standard, as opposed to the ChromeCast, it's just that Sony is shit at implementing the standard). I can play music from Spotify from my laptop or smartphone on a Denon speaker in the kitchen, a "GramoFon" wifi-sound-device attached to my "dumb" stereo and my dad's "smart" Marantz stereo.
Interoperability is doing fine, but yes, it's messier than it might have been if some magic omniscient body had come up with clean standards for all this. That doesn't mean that it's not there.